scholarly journals Investigation on Atomic Structure and Mechanical Property of Na- and Mg-Montmorillonite under High Pressure by First-Principles Calculations

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 613
Author(s):  
Jian Zhao ◽  
Yu Cao ◽  
Lei Wang ◽  
Hai-Jiang Zhang ◽  
Man-Chao He
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Band Structure ◽  
Electronic Properties ◽  
Wave Velocity ◽  
Atomic Structure ◽  
Density Functional ◽  
External Pressure ◽  
Ideal Condition ◽  
Lattice Constants

Montmorillonite is an important layered phyllosilicate material with many useful physicochemical and mechanical properties, which is widely used in medicine, environmental protection, construction industry, and other fields. In order to a get better understanding of the behavior of montmorillonite under high pressure, we studied its atomic structure, electronic and mechanical properties using density functional theory (DFT), including dispersion corrections, as function of the interlayer Na and Mg cations. At ideal condition, the calculations of lattice constants, bond length, band structure, and elastic modulus of Na- and Mg-montmorillonite are in good agreement with the experimental values. Under high pressure, the lattice constants and major bond lengths decreased with increasing pressure. The calculated electronic properties and band structure show only a slight change under 20 GPa, indicating that the effect of pressure on the electronic properties of Na- and Mg-montmorillonite is weak. The bulk modulus, shear modulus, Young’s modulus, shear wave velocity and compression wave velocity of Na- and Mg-montmorillonite are positively correlated with the external pressure, and the other mechanical parameters have a little change. The calculated studies will be useful to explore experiments in the future from a purely scientific point of view.

scholarly journals Atomic Structure, Electronic and Mechanical Properties of Pyrophyllite under Pressure: A First-Principles Study

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 778
Author(s):  
Xinzhan Qin ◽  
Jian Zhao ◽  
Jiamin Wang ◽  
Manchao He
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Atomic Structure ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Electronic Density ◽  
Functional Theory ◽  
Wide Range ◽  
Pressure Transmission ◽  
Pressure Synthesis

Pyrophyllite is extensively used in the high-pressure synthesis industry as a pressure-transmitting medium because of its outstanding pressure transmission, machinability, and insulation. Therefore, the atomic structure, electronic, and mechanical behavior of pyrophyllite [Al4Si8O20(OH)4] under high pressure should be discussed deeply and systematically. In the present paper, the lattice parameters, bond length, the electronic density of states, band structure, elastic constants, and mechanical parameters of pyrophyllite are investigated using density functional theory (DFT) from a microscopic perspective. The pressure dependence of atomic structure, electronic, and mechanical properties of pyrophyllite is analyzed for a wide range of pressure (from 0 GPa to 13.87 GPa). Under high pressure, the major bond lengths and layer thicknesses decrease slightly, and mechanical properties are improved with increasing pressure. The calculated electronic and band structures show only a slight change with increasing pressure, implying that the effect of pressure on the electronic property of pyrophyllite is weak, and pyrophyllite still has good stability under high pressure. The theoretical calculations presented here clarify the electronic and mechanical properties of natural pyrophyllite that are difficult to obtain experimentally because of their small particle size.

scholarly journals First-principles studies on band structure and mechanical properties of BiFeO3 ceramics under high pressure

2017 ◽  
Vol 11 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Ramanathan Chandiramouli ◽  
Veerappan Nagarajan
Keyword(s):  
Mechanical Properties ◽  
Density Functional Theory ◽  
High Pressure ◽  
Band Structure ◽  
First Principles ◽  
Density Functional ◽  
Applied Pressure ◽  
Functional Theory ◽  
Increasing Trend ◽  
G Ratio

Mechanical properties and band structure of rhombohedral BiFeO3 nanostructures were studied using density functional theory for different pressures in the range from 0 to 50GPa. The elastic constant of BiFeO3 nanoceramics was determined and different moduli were calculated for various applied pressures. The bulk (B) and shear (G) modulus show an increasing trend on applied high pressure. The findings of the present work also confirm that the hardness of BiFeO3 increases with the applied pressure. The ductility of BiFeO3 nanostructure increases upon increasing the pressure, which is confirmed from Poisson?s ratio and B/G ratio. The band structure studies were also carried out under high pressure and showed that the band gap decreases upon increase in the applied pressure.

scholarly journals Study of Structural and Electronic Properties of Intercalated Transition Metal Dichalcogenides Compound MTiS2 (M = Cr, Mn, Fe) by Density Functional Theory

2021 ◽  
Keyword(s):  
Transition Metal ◽  
Band Structure ◽  
Electronic Properties ◽  
Density Of States ◽  
Density Functional ◽  
Transition Metal Dichalcogenides ◽  
Energy Band Structure ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

In the present work, we have studied intercalated Transition Metal Dichalcogenides (TMDC) MTiS2 compounds (M = Cr, Mn, Fe) by Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA). We have computed the structural and electronic properties by using first principle method in QUANTUM ESPRESSO computational code with an ultra-soft pseudopotential. A guest 3d transition metal M (viz; Cr, Mn, Fe) can be easily intercalated in pure transition metal dichalcogenides compound like TiS2. In the present work, the structural optimization, electronic properties like the energy band structure, density of states (DoS), partial or projected density of states (PDoS) and total density of states (TDoS) are reported. The energy band structure of MTiS2 compound has been found overlapping energy bands in the Fermi region. We conclude that the TiS2 intercalated compound has a small band gap while the doped compound with guest 3d-atom has metallic behavior as shown form its overlapped band structure.

scholarly journals Mechanical properties and band structure of CdSe and CdTe nanostructures at high pressure - a first-principles study

2019 ◽  
Vol 13 (2) ◽  
pp. 124-131 ◽  
Author(s):  
Natarajan Kishore ◽  
Veerappan Nagarajan ◽  
Ramanathan Chandiramouli
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Shear Modulus ◽  
Band Structure ◽  
First Principles ◽  
Pressure Range ◽  
Uniaxial Pressure ◽  
First Principles Calculations ◽  
Zinc Blende ◽  
Cauchy Pressure

First-principles calculations for CdSe and CdTe nanostructures were carried out to study their mechanical properties and band structure under the uniaxial pressure range of 0 to 50GPa. It was presumed that the CdSe and CdTe nanostructures exist in the zinc-blende phase under high pressure. The mechanical properties, such as elastic constants, bulk modulus, shear modulus and Young?s modulus, were explored. Furthermore, Cauchy pressure, Poisson?s ratio and Pugh?s criterion were studied under high pressure for both CdSe and CdTe nanostructures, and the results show that they exhibit ductile property. The band structure studies of CdSe and CdTe were also investigated. The findings show that the mechanical properties and the band structures of CdSe and CdTe can be tailored with high pressure.

Structural, electronic, and mechanical properties of anatase titanium dioxide

2019 ◽  
Vol 15 (2) ◽  
pp. 306-316 ◽  
Author(s):  
Debashish Dash ◽  
Chandan Kumar Pandey ◽  
Saurabh Chaudhary ◽  
Susanta Kumar Tripathy
Keyword(s):  
Mechanical Properties ◽  
Titanium Dioxide ◽  
Electronic Properties ◽  
Density Functional ◽  
Paper Industry ◽  
Ground Level ◽  
Basis Set ◽  
Indirect Transition ◽  
Content Type ◽  
Valence Region

PurposeThe purpose of this paper is to analyze various properties of anatase titanium dioxide (TiO2) nanoparticles. Further, it proposes to implement Linear Combinations of Atomic Orbitals (LCAO) basis set under the framework of density functional theory and outline how LCAO is able to provide improved results in terms of various mechanical properties rather than plane wave and other theoretical results.Design/methodology/approachThis paper provides an exploratory study on anatase TiO2by implementing OLCAO–DFT–LDA–LBFGS–EOS–PZ algorithms to find out various ground-level properties. The data so obtained are complemented by various analysis using mathematical expressions, description of internal processes occurred and comparison to others’ analytical results.FindingsThe paper provides some empirical insights on how mechanical properties of anatase TiO2improved by implementing LCAO methodology. From the analysis of electronic properties, it is seen that the anatase TiO2supports the inter band indirect transition from O-2p in valence region to Ti-3d in the conduction region.Research limitations/implicationsMost of the electronic properties are underestimated because a single exchange-correlation potential is not continuous across the gap. This gap can be enhanced by implementing Green’s function in place of DFT and the other way is to implement self-interaction correction.Practical implicationsThe use of anatase TiO2is primarily used for catalytic applications. This is also used to enhance the quality of paper in the paper industry. Additionally, this is used as a prime ingredient in cosmetic industry.Originality/valueThis paper fulfills an identified need to study how LCAO, another basis set, plays an important role in improving material properties.

scholarly journals DFT Calculations of the Structural, Mechanical, and Electronic Properties of TiV Alloy Under High Pressure

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 972 ◽  
Author(s):  
Fang Yu ◽  
Yu Liu
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Electronic Properties ◽  
Structural Phase Transition ◽  
Density Functional ◽  
Structural Phase ◽  
Applied Pressure ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Dimensionless Ratio

A calculation program based on the density functional theory (DFT) is applied to study the structural, mechanical, and electronic properties of TiV alloys with symmetric structure under high pressure. We calculate the dimensionless ratio, elastic constants, shear modulus, Young’s modulus, bulk modulus, ductile-brittle transition, material anisotropy, and Poisson’s ratio as functions of applied pressure. Results suggest that the critical pressure of structural phase transition is 42.05 GPa for the TiV alloy, and structural phase transition occurs when the applied pressure exceeds 42.05 GPa. High pressure can improve resistance to volume change, as well as the ductility and atomic bonding, but the strongest resistances to elastic and shear deformation occur at P = 5   GPa for TiV alloy. Furthermore, the results of the density of states (DOS) indicate that the TiV alloy presents metallicity. High pressure disrupts the structural stability of the TiV alloy with symmetry, thereby inducing structural phase transition.

Structural, elastic, magnetic and electronic properties of Ti-based Heusler alloys

2020 ◽  
Vol 34 (07) ◽  
pp. 2050055 ◽  
Author(s):  
R. Murugeswari ◽  
M. Manikandan ◽  
R. Rajeswarapalanichamy ◽  
A. Milton Franklin Benial
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Energy Gap ◽  
Ambient Pressure ◽  
Magnetic Moments ◽  
Heusler Alloys ◽  
Text Structure ◽  
Simulation Code ◽  
Text Type ◽  
Lattice Constants

The structural, elastic, magnetic and electronic properties of titanium-based alloys [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] are investigated by the first-principles calculations based on density functional theory using the Vienna ab-initio simulation code. The lattice constants of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are optimized for the two possible structures such as [Formula: see text] and [Formula: see text]. It is found that at ambient pressure [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are stable in [Formula: see text]-type crystal structure. The total magnetic moments [Formula: see text] and the energy gap [Formula: see text] of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys are calculated for various pressures. The total magnetic moments of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys in [Formula: see text] structure follow the rule [Formula: see text] and agree with the Slater–Pauling (SP) curve quite well. In both structures [Formula: see text] and [Formula: see text], the calculated magnetic moment of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys decreases with increase in pressure. Density of states shows the metallic nature of [Formula: see text] [Formula: see text], [Formula: see text] and [Formula: see text] alloys in [Formula: see text] structure and half-metallic [Formula: see text] behavior in [Formula: see text] structure, i.e., majority spin channel is strongly metallic and the minority spin maintains the gap at the Fermi level at the equilibrium lattice constant.

scholarly journals Pressure Dependence of Structural and Mechanical Properties of Single-Crystal Tungsten: A Molecular Dynamics Study

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1898
Author(s):  
Xuepeng Liu ◽  
Kezhong Xu ◽  
Hua Zhai
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
High Pressure ◽  
Single Crystal ◽  
Pressure Dependence ◽  
High Pressures ◽  
External Pressure ◽  
Uniaxial Tensile ◽  
Linear Lattice ◽  
Lattice Contraction

In the current study, molecular dynamics (MD) simulations were performed to study the pressure dependence of the structural and mechanical properties of single-crystal tungsten. The results show that single-crystal tungsten possesses noteworthy high-pressure stability and exhibits linear lattice contraction with increasing external pressure. Consistent with the results of the performed experiments, the predicted elastic moduli, including Young’s modulus, shear modulus, and bulk modulus, as well as Poisson’s ratio and Pugh’s modulus ratio, show a clear increasing trend with the increase in pressure. Under uniaxial tensile loading, the single-crystal tungsten at high pressures experiences a phase transition from BCC to FCC and other disordered structures, which results in a stripe-like morphology in the tungsten crystal. These results are expected to deepen our understanding of the high-pressure structural and mechanical behaviors of tungsten materials.

Elastic and Electronic Properties of Mg2Ca and Mg2Y Phases

2011 ◽  
Vol 233-235 ◽  
pp. 2231-2238 ◽  
Author(s):  
Meng Xue Zeng ◽  
Bi Yu Tang ◽  
Li Ming Peng ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Properties ◽  
Electronic Properties ◽  
Structural Stability ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Underlying Mechanism ◽  
Point Of View ◽  
Electronic Density ◽  
Energetic Point ◽  
Two Phases

Elastic and electronic properties of Mg2Ca and Mg2Y phases were investigated from first-principles calculations based on density functional theory. The optimized lattice parameters were found to be in excellent agreement with the available experimental value, and the structural stability was also studied from the energetic point of view. The five independent elastic constants were calculated, then the bulk modulus B, shear modulus G, Young’s modulus E and Poisson’s ratio ν of polycrystalline aggregates were derived, and the relevant mechanical properties Mg2Ca and Mg2Y phases were also further discussed. The elastic anisotropy of the two phases was also discussed in details. Finally, the electronic density of states and charge density distribution were also calculated to reveal the underlying mechanism of structural stability and mechanical properties.

Pressure effect on the mechanical and electronic properties of orthorhombic-C20

2018 ◽  
Vol 32 (31) ◽  
pp. 1850380 ◽  
Author(s):  
Jian-Li Ma ◽  
Zhi-Fen Fu ◽  
Qun Wei ◽  
Peng Liu ◽  
Jian-Ping Zhou
Keyword(s):  
High Pressure ◽  
Electronic Properties ◽  
Debye Temperature ◽  
Density Functional ◽  
Superhard Material ◽  
Elastic Anisotropy ◽  
Systematic Investigation ◽  
Functional Theory ◽  
Temperature Changes ◽  
The Density Functional Theory

A systematic investigation of structural, mechanical, elastic anisotropy and electronic properties of a recently reported novel superhard material orthorhombic [Formula: see text] ([Formula: see text]-[Formula: see text]) under pressure is performed utilizing the density functional theory in this work. The crystal structure parameters are obtained at zero as well as at high pressure. Pressure induced elastic constants [Formula: see text], polycrystalline aggregate elastic modulus [Formula: see text], [Formula: see text] ratio, and Debye temperature changes for [Formula: see text]-[Formula: see text] have been determined. The crystal elastic anisotropies of the ultra-incompressible [Formula: see text]-[Formula: see text] are investigated in the pressure range of 0–100 GPa. The Lyakhov–Oganov model is applied to predict the hardness as functions of pressure. The calculated results reveal that [Formula: see text]-[Formula: see text] possesses high elastic anisotropy under zero pressure and high pressure, and the hardness of [Formula: see text]-[Formula: see text] decreases with pressure, while the Debye temperature behaves with the opposite trend. The results of electronic structure indicate that [Formula: see text]-[Formula: see text] exhibits insulator characteristics, and the band gap increases with pressure. This work is expected to provide a useful guide for the future synthesis and application of [Formula: see text]-[Formula: see text].

Sign in / Sign up

Export Citation Format

Share Document